University of Carthage, Faculty of Sciences of Bizerte, Laboratory of Environment Biomonitoring, Coastal Ecology and Ecotoxicology Unit, 7021, Zarzouna, Tunisia.
King Saud University, Zoology Department, College of Science, Box 2455, Riyadh, 11451, Saudi Arabia.
Environ Pollut. 2020 Jul;262:114350. doi: 10.1016/j.envpol.2020.114350. Epub 2020 Mar 12.
A laboratory bioassay was conducted to investigate the ecotoxicity of a chromium-enriched superfood, Spirulina platensis, on the meiofauna collected from the Ghar El Melh lagoon, Tunisia. After 1 month of exposure, the abundances of meiobenthic taxa and the taxonomic and morpho-functional diversity of nematodes showed significant differences between the Spirulina and Spirulina + chromium groups. The nematodes were more tolerant of all types of stressors compared to harpacticoids, polychaetes, and oligochaetes, and the lowest taxonomic and morpho-functional diversity of nematodes was observed in the highest sedimentary concentration of S. platensis (50% DW). The mixed treatments may have been richer in micro-habitats and subject to low selective pressure, thereby hosting nematodes with a wide range of adaptations. The responses of the nematode species differed depending on their functional traits. Spirulina enriched with chromium induced two responses for the same feeding group: high toxicity for Daptonema fallax and low toxicity for two Theristus species (T. flevensis and T. modicus). The ecotoxicity of the Spirulina/chromium mixtures were lower than that of Spirulina alone, suggesting mutual neutralization between these two elements. The association between functional traits and taxonomic diversity showed that the effects of the mixtures were not additive and that one of the stressors camouflaged the effect of the other. Our findings should encourage the commercialization of chromium-enriched S. platensis owing to its lower ecotoxicity than Spirulina alone.
进行了一项实验室生物测定，以研究富铬超级食品螺旋藻对来自突尼斯加尔梅尔赫泻湖的小型底栖动物的生态毒性。暴露 1 个月后，螺旋藻和螺旋藻+铬组之间的小型底栖动物分类群丰度以及线虫的分类和形态功能多样性均显示出显著差异。与桡足类、多毛类和寡毛类相比，线虫对所有类型的胁迫更具耐受性，而在螺旋藻沉积浓度最高（50%DW）的地方，线虫的分类和形态功能多样性最低。混合处理可能含有更丰富的微生境，受到的选择压力较低，从而容纳了具有广泛适应性的线虫。线虫物种的反应因功能特征而异。富铬螺旋藻对同一摄食群诱导了两种反应：对 Daptonema fallax 具有高毒性，对两种 Theristus 物种（T. flevensis 和 T. modicus）具有低毒性。螺旋藻/铬混合物的生态毒性低于单独的螺旋藻，表明这两种元素相互中和。功能特征与分类多样性之间的关联表明，混合物的影响不是加性的，其中一种胁迫因素掩盖了另一种胁迫因素的影响。我们的研究结果应该鼓励商业化生产富铬螺旋藻，因为它的生态毒性低于单独的螺旋藻。
